1. Field of the Invention
The present invention relates to an adjustment of a tracking curve used in a tracking control which keeps an in-focus state for an object distance during a variation of magnification.
2. Description of the Related Art
In a tracking control, a focus lens is moved in accordance with a tracking curve that is configured to keep an in-focus state between a position (or a focal length) of a variator lens in a zoom lens (magnification-varying lens) and a position of a focus lens for an object distance. This tracking curve is derived from a designed value of an optical element, but the tracking curve obtained from the designed value may shift from an actual tracking curve due to an attachment error or a manufacturing error of the optical element. In this case, it is required to adjust the tracking curve for each image-pickup apparatus (for example, Japanese Patent Laid-Open Nos. (“JP”) 08-220414, and 11-183775).
This inventor attempts to develop a tracking control method by moving both a focus lens and an image sensor in order to achieve a wider angle, a higher magnification, and a smaller size. No prior art propose a method for adjusting the tracking curves between them. For example, each of JP08-220414 and JP11-183775 moves the focus lens in the tracking control, but does not move the image sensor.